Some iPhone 4 launch units lose signal when held with left hand

Some users have experienced poor signal and dropped calls when holding Apple's new iPhone 4 in their left hand, which makes their palm cover a seam that separates the device's two perimeter radio antennas.

When Apple announced the iPhone 4 earlier this month, the company revealed that the metal band around the outside of the device has breaks in it to allow the multiple antennas inside the device —for cellular service, Wi-Fi, Bluetooth and more —to establish connections. The larger metal piece on the right side of the phone serves as the GSM/UMTS cellular antenna, and the smaller portion on the left side is responsible for Bluetooth, Wi-Fi and GPS.

For some, covering —or even just touching —the point where the two antennas meet on the left side of the phone can cause loss of signal (via Insanely Great Mac) and even dropped calls. The reports suggest that the issue is worse than the problem described by Walt Mossberg of The Wall Street Journal.

In his review of the iPhone 4, Mossberg said that the device sometimes registers no bars, or fewer bars than the iPhone 3GS, even though a call can still be placed. He spoke with Apple about the issue, and the company said they are aware and are working on a patch to resolve it.

But as noted by Engadget, some users actually do lose reception and experience dropped calls when covering the antenna seam on the left side of the device, naturally done when holding the phone in one's left hand.

"One iPhone 4 demonstrated the issue every time it was held in our left hand (as a right-handed person is apt to do) so that our palm was essentially bridging the two antennas)," the report said.

It continued: "Bridging the two with a finger tip, however, didn't cause any issues with the reported reception. If we had to guess, we'd say that our conductive skin was acting to detune the antenna —in fact, we've already managed to slowly kill two calls that way so it's not just an issue with software erroneously reporting an incorrect signal strength."

Others, however, have experienced the issue simply by touching the seam where the two antennas meet with a fingertip. However, the review unit given to the tech blog before the release of the iPhone 4 did not experience any of these issues, suggesting it does not apply to all handsets.

The report went on to note that the problems disappeared when the official rubber "bumper" protective case, sold by Apple for $29, is attached to the handset.